[PATCH RFC v3 4/4] vhost/net: add an option to test new code

["Michael S. Tsirkin" <mst@xxxxxxxxxx>]

Add a writeable module parameter that tests
the new code. Note: no effort was made to ensure
things work correctly if the parameter is changed
while the device is open. Make sure to
close the device before changing its value.

Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
 drivers/vhost/net.c | 32 +++++++++++++++++++++++++-------
 1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 1a2dd53caade..122b666ec1f2 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -35,6 +35,9 @@
 
 #include "vhost.h"
 
+static int newcode = 0;
+module_param(newcode, int, 0644);
+
 static int experimental_zcopytx = 0;
 module_param(experimental_zcopytx, int, 0444);
 MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;"
@@ -565,8 +568,14 @@ static int vhost_net_tx_get_vq_desc(struct vhost_net *net,
 	struct vhost_virtqueue *rvq = &rnvq->vq;
 	struct vhost_virtqueue *tvq = &tnvq->vq;
 
-	int r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
-				  out_num, in_num, NULL, NULL);
+	int r;
+
+	if (newcode)
+		r = vhost_get_vq_desc_batch(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
+					    out_num, in_num, NULL, NULL);
+	else
+		r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
+				      out_num, in_num, NULL, NULL);
 
 	if (r == tvq->num && tvq->busyloop_timeout) {
 		/* Flush batched packets first */
@@ -575,8 +584,12 @@ static int vhost_net_tx_get_vq_desc(struct vhost_net *net,
 
 		vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, false);
 
-		r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
-				      out_num, in_num, NULL, NULL);
+		if (newcode)
+			r = vhost_get_vq_desc_batch(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
+						    out_num, in_num, NULL, NULL);
+		else
+			r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
+					      out_num, in_num, NULL, NULL);
 	}
 
 	return r;
@@ -1046,9 +1059,14 @@ static int get_rx_bufs(struct vhost_virtqueue *vq,
 			r = -ENOBUFS;
 			goto err;
 		}
-		r = vhost_get_vq_desc(vq, vq->iov + seg,
-				      ARRAY_SIZE(vq->iov) - seg, &out,
-				      &in, log, log_num);
+		if (newcode)
+			r = vhost_get_vq_desc_batch(vq, vq->iov + seg,
+						    ARRAY_SIZE(vq->iov) - seg, &out,
+						    &in, log, log_num);
+		else
+			r = vhost_get_vq_desc(vq, vq->iov + seg,
+					      ARRAY_SIZE(vq->iov) - seg, &out,
+					      &in, log, log_num);
 		if (unlikely(r < 0))
 			goto err;
 
-- 
MST